Epidemiology of TB

Which countries have high rates of TB?

Ninety-five percent of all tuberculosis cases in the world occur in developing countries. Tuberculosis is prevalent in Russia, India, Southeast Asia, sub-Saharan Africa, and parts of Latin America. Countries with a high prevalence of HIV infection have the greatest tuberculosis burden.

The following ten countries of origin account for the largest number of TB cases among immigrants:Mexico, Philippines, Vietnam, India, China, Haiti, South Korea, Guatemala, Ethiopia, and Peru

(Number of cases per 100,000 population)

What is the risk of tuberculosis among immigrants?

In the US, over half of all active TB cases occur in immigrants. The reported cases of active TB in foreign-born persons has remained at 7000-8000 per year, while the number of cases in US-born people has dropped from 17,000 in 1993 to 6,500 in 2005. As a result, the percentage of active TB cases in immigrants has increased steadily (from 29% of all cases in 1993 to 54% in 2005).

Cases of TB in US-born vs. Foreign-born persons:

The risk of latent disease progressing to active tuberculosis is highest in the first few years after immigration, which is why newly-arrived immigrants (within five years) are a priority for testing and treatment. However, half of all TB reactivations in immigrants occur after their first five years in the US, so testing this group should be encouraged as well.